In the past, radio resources are scarce and trilateration was carried out in deterministic ways. Nowadays, due to proliferation of mobile wireless devices and fixed access points (APs), data needed to carry out trilateration can be collected easily. By using the sea amount of radio measurement data while mobile devices are moving around, more accurate assessment of the locations of those mobile devices relative to the stationary APs can become available, even without the client device users' awareness. Statistic means including averaging, mean square value, channel estimation, Kalman filter, fingerprinting, etc. will only increase the accuracy of the location assessment. Means of radio measurement may include signal strength, angle of arrival (triangulation), time or phase of arrival. Mixed use of these means, with appropriate inclusion of Probabilistic methods, will increase the accuracy.